Town · The Kamakura house and its housemen · as at first light, 1 January 1200

Oyama

Oyama on the Kinu and Watarase plain in Shimotsuke is the seat of the Oyama house and of its head Oyama Tomomasa, constable of Shimotsuke.

It stands at the road crossing to the Yūki lands and the Ashikaga.

Who holds it

Name
Oyama Tomomasa
Title
Head of the Oyama and constable of Shimotsuke
Since
1190s
Born
1155
Family
See the lord record.
Confidence
high

English Wikipedia (Oyama Tomomasa).

Lord in 1200

Oyama Tomomasa

Where the sources disagree

Evidence: Recollection and the campaign board; no page on the place was opened.

"The campaign board" is OMNIA's working map. These notes record where its earlier claims were checked against the sources.

On the map: Seat only.

Primary sources for Kamakura regime

Chronicles, registers, sagas and inscriptions written in or near 1200 that cover this entry. Each has its own page with editions, translations and where to read it.

  • Hundred Times Refined Extracts: court annals (late thirteenth century, from court diaries). Short dated annals of the imperial court excerpted from courtiers' diaries, among them the Gyokuyo and the Meigetsuki. Read online
  • Mirror of the East, Anonymous; compiled by officials of the Kamakura shogunate (compiled about 1300 from the shogunate's records, diaries and family documents). The Kamakura house's own chronicle, in daily entries. Read online
  • Jottings of a Fool: an interpretative history of Japan, Jien (慈円) (about 1219 to 1220, revised to about 1223). A history by Kujo Kanezane's brother, head of the Tendai school and the leading churchman of the court, written to explain the fall of the Kujo and the rise of the warriors as the working of principle (dori). Read online
  • Diary of the Inokuma Regent: the diary of Konoe Iezane, Konoe Iezane (近衛家実) (1197 to 1218, as a daily diary). The diary of the regent's heir, aged twenty-one in 1200 and already a senior courtier under his father Konoe Motomichi, who was regent (sessho) for the child emperor Tsuchimikado. Read online
  • Leaves of Jade: the diary of Kujo Kanezane, Kujo (Fujiwara) Kanezane (九條兼實) (1164 to 1200, as a daily diary). The diary of the former regent, Yoritomo's ally at court, who had been driven from power in the Kenkyu purge of 1196 and lived in retirement in 1200. Read online
  • Record of the Bright Moon: the diary of Fujiwara no Teika, Fujiwara no Teika (藤原定家) (1180 to 1235, as a daily diary, with gaps). The diary of the poet and courtier, then thirty-eight and a middle-ranking official of the Kujo house. Read online
  • Surviving Documents of the Kamakura Period, Various; collected by Takeuchi Rizo (竹内理三) (documents of 1185 to 1333, collected and printed 1971 to 1997). The collected charters, deeds, court orders, shogunal directives, temple records and land registers of the Kamakura age, printed in date order. Read online
  • The Tale of the Heike, Anonymous; traditionally attributed to Shinano no Zenji Yukinaga, performed and reshaped by blind reciters (early thirteenth century in its first form; the standard Kakuichi text was fixed in 1371). The epic of the Genpei war, in the form the reciters gave it over the century after 1200. Read online

Sources and studies

  1. KJA_BRIEF.md and the OMNIA board for sheet kja (the lead's notes: [own] computation, [not yet checked against the source] recollection, [en] English Wikipedia)
  2. Azuma Kagami (the Kamakura chronicle), Kenkyu 10 to Shoji 2 entries, recalled and through the brief; ja.wikipedia and ja.wikisource were refused in this session, so no entry was re-read
  3. Jeffrey P. Mass, Warrior Government in Early Medieval Japan (1974), from memory; the archive.org full text could not be opened
  4. English Wikipedia: Oyama Tomomasa (read this session; thin)

Last revised 4 November 2026. Published 4 November 2026. Suggest a correction on the OMNIA Discord.